Dear editor

In the last issue of the journal, a review of tennis elbow and its management in tennis players appears. It is disappointing to see that the journal publishes a review with misleading treatment recommendations. The review article suffers from the inherent weaknesses of the narrative review form with an unjustified favourisation of "promising" pharmacological and surgical interventions. Physical interventions are not even mentioned in the conclusion, and the authors state that there is “no scientific evidence regarding the efficacy in the long term of the currently used conservative treatment options”. In addition, they recommend that “a wait-and-see approach is initially advised, as long-term results do not differ significantly between groups, but if complaints persist, a surgical approach can be considered”. In the treatment section of the review, steroid injections are claimed to be beneficial in the short term and not significantly different from other treatments in the long and intermediate term. This statement does not reflect the available evidence. Physiotherapy is acting faster than wait-and-see with significantly better results at 6 weeks [1], while physiotherapy is significantly better than steroid injections at 12, 26 and 52 weeks [2]. Thus, from a safety perspective it can be concluded that steroid injections increase the risk for chronic disability and possible permanent tendon damage [3]. It remains unanswered whether this negative effect is reversible or not in a timeframe beyond one year. Consequently, steroid injections should be discouraged in the management of tennis elbow. Regarding surgery, there is a scarcity of randomized controlled trials, and we found only one randomized trial showing no difference over botox injections [4]. The self-limiting nature of tennis elbow with scientific evidence showing a 92% success rate at 1 year after physiotherapy [2], leaves no place for surgery with the inherent risks and lack of documented effects in tennis elbow management. The final word about the contents of an optimal physiotherapy package for tennis elbow has probably not been said. The review cites two references with low level laser therapy (LLLT) reviews, which have missed large parts of the LLLT literature, and fail to address the validity of doses and LLLT procedures. Three LLLT-trials with positive results which we included in our 2001 LLLT-review of tendinopathies[5] were omitted from these reviews. One of the omitted trials showed a significantly positive short-term effect for LLLT over placebo in recreational tennis players [6]. Another two LLLT trials with exercise therapy regimens in tennis elbow from 2007 show that the addition of 904 nm LLLT with valid doses provides significantly faster pain-relief than placebo LLLT and exercises [7, 8]. From the above, modification of sports activity and an active approach with a physiotherapy package containing exercises, stretching, mobilisation and possibly LLLT emerges as the new gold standard in tennis elbow management. There is certainly no need to consider steroid injections or surgery for the average patient with tennis elbow complaints, when effective risk-free alternatives exist.

References

1. Bisset, L., et al., Mobilisation with movement and exercise, corticosteroid injection, or wait and see for tennis elbow: randomised trial. BMJ, 2006. 333(7575): 939.

2. Bisset, L., et al., Conservative treatments for tennis elbow do subgroups of patients respond differently? Rheumatology (Oxford), 2007. 46(10): 1601-5.

3. Smidt, N. and D.A. van der Windt, Tennis elbow in primary care. BMJ, 2006. 333(7575): 927-8.

4. Keizer, S.B., et al., Botulinum toxin injection versus surgical treatment for tennis elbow: a randomized pilot study. Clin Orthop Relat Res, 2002(401): 125-31.

5. Bjordal, J., C. Couppé, and A. Ljunggreen, Low level laser therapy for tendinopathy. Evidence of a dose-response pattern. Physical Therapy Reviews, 2001. 6(2): 91-99.

6. Palmieri, B., Stratified double blind crossover study on tennis elbow in young amateur athletes using infrared lasertherapy. Medical Laser Report, 1984. 1: 1.

7. Lam, L.K. and G.L. Cheing, Effects of 904-nm Low-Level Laser Therapy in the Management of Lateral Epicondylitis: A Randomized Controlled Trial. Photomed Laser Surg, 2007. 25(2): 65-71.

8. Stergioulas, A., Effects of low-level laser and plyometric exercises in the treatment of lateral epicondylitis. Photomed Laser Surg, 2007. 25(3): 205-13.

Dear editor

Re:Do you get value for money when you buy an expensive pair of running shoes? [1]

When the ground-force-reaction is measured as a function of time during running or walking, the result is a function of speed and underfoot conditions [2]. At any speed, however, the area under the force-time plot represents the total momentum change during the stance phase of gait. This cannot be altered by any shoe design, since the consequence would be that the runner would either rise up into the air or sink lower and lower with bent knees. At the start of the contact phase, the centre of mass of the runner is moving downwards. At the end of the contact phase, the centre of mass is moving upwards – the motion must be exactly reversed. Attempts to find a design of running shoe that will alter the ground-force-reaction are doomed to failure for this reason.

It was shown, however, by McMahon & Greene [3]that if the underfoot compliance were to be chosen in the range 100-200kN/m, then the spike seen in the GRF-time plot, as a result of heel impact, will not be observed.

The basic premise of Clinghan et al, that changes should be detectable in the GRF as a result of differences in shoe design between expensive and inexpensive shoes, may be seen to be one that would not survive experimental inquiry. In fact, their results were defined before any tests were carried out, since no differences can be found.

The fact that differences were seen between different areas of the foot may be put down to experimental variation, and the fact that while the GRF cannot be changed radically, it is possible to redistribute the force across the foot.

References

1. Clinghan R T, Arnold G P,Drew T S, Cochrane L, and Abboud R J Do you get value for money when you buy an expensive pair of running shoes? Br J Sports Med 2007.038844v1

2.Walker CA & Blair R Leg stiffness and damping factors as a function of running speed, Sports Engineering 2002, 5, 129-139.

3. McMahon TA & Greene PR The influence of track compliance on running, J. Biomech. 1979, 12, 893-904.

Dear Editor

What is important is that coaches must apply the Laws when coaching the game. Referees however must apply the Laws when refereeing at any level of competition. At the Rugby World Cup the post tackle events and the ruck were consistently poorly refereed. Only the tackled player and the tackler(s) are permitted to be off their feet and no one else. In the matter of the scrum that Law prohibits the front rows from charging towards each other. Another important issue is the repetitive contacts between players in the tackle situation and the scrum which over time develops into chronic tissue damage. Such events have led to instability of the shoulder and the acj joints affecting the tackler and premature degeneration of the cervical spine in front row forwards. The study on post match tackle injuries by Takarada (2003)[1] highlights the effects of the contacts made at the tackle.I believe the tackle law can deserve another update.

References
1.Takarada, Y. (2003). Evaluation of muscle damage after a rugby match with special reference to tackled players. British Journal of Sports Medicine, 37(5), 416-419. The International Rugby Board. (2007). Laws of the game. Dublin: The International Rugby Board.

Dear Editor,

In a recent letter,[7] Noakes reminded us that the brain estimates the maximal exercise duration that can be sustained (maybe even before the exercise begins), and then uses the ratings of perceived exertion (RPE) to inform the body when the exercise will and must terminate. I agree with this suggestion. RPE attests to the exercise intensity, but also to the duration.[3] Therefore, according to Noakes,[7, 8] RPE is a predictor of the exercise duration that remains until exhaustion. However, RPE is not the only perceptual tool that informs us of the exercise end point, and perhaps not the most effective.

Drawing from the “teleoanticipation” concept,[9] prior to, or early in an exercise period, the brain estimates the time limit (i.e., Tlim) that can safely sustained.[8] Then, this predicted Tlim is associated with the maximal RPE that can be tolerated. During exercise, the brain provides RPE, which increases as a function of the percentage of the predicted Tlim, until the attainment of the corresponding tolerated maximal RPE.[8]

Garcin and Billat confirmed that RPE attests to both exercise intensity and duration.[3] However, these authors[3] found similar results for a second scale (Estimated Time Limit scale, ETL). This scale predicts how long the current exercise level can be maintained (i.e., the estimation of exhaustion time). Therefore, as suggested by Noakes,[7] if humans may accurately predict the exercise duration that they are or will be able to sustain at any exercise intensity, ETL may be considered as the conscious interpretation of the Tlim predicted by teleoanticipation, and may be more effective than RPE in predicting the time remaining before exhaustion.

The reliability of ETL scale is established.[1, 5] Moreover, although the accuracy of this scale must be improved, no significant difference was found between the Tlim predicted from this scale and those that were actually measured.[1, 2, 4] Therefore, ETL scale may be associated with the RPE scale (or substituted for the RPE scale, if the accuracy improves), not to precisely measure the Tlim predicted by teleoanticipation, but to provide an estimation of this latter, as recently suggested.[6]

There are no competing interests.

References

1. Coquart, J. B. J. and M. Garcin. Validity and reliability of perceptually-based scales during exhausting runs in trained male runners. Percept Mot Skills. 2007;104:254-266.
2. Coquart, J. B. J., M. Garcin, S. Robin, and R. Matran. Prediction of exhaustion time from a perceptually-based scale. In 12th International Congress of the Association des Chercheurs en Activités Physiques et Sportives. Leuven, Belgium, p. 68, 2007.
3. Garcin, M. and V. Billat. Perceived exertion scales attest to both intensity and exercise duration. Percept Mot Skills. 2001;93:661-671.
4. Garcin, M., L. Mille-Hamard, and V. Billat. Influence of aerobic fitness level on measured and estimated perceived exertion during exhausting runs. Int J Sports Med. 2004;25:270-277.
5. Garcin, M., M. Wolff, and T. Bejma. Reliability of rating scales of perceived exertion and heart rate during progressive and maximal constant load exercises till exhaustion in physical education students. Int J Sports Med. 2003;24:285-290.
6. Joseph, T., B. Johnson, R. A. Battista, G. Wright, C. Dodge, J.P. Porcari, J. J. De Koning, and F. Foster. Perception of fatigue during simulated competition. Med Sci Sports Exerc. 2008;40:381-386.
7. Noakes, T. D. RPE as a predictor of the duration of exercise that remains until exhaustion. Br J Sports Med Oneline [eLetter] 8 January 2008. http://bjsm.bmj.com/cgi/content/abstract/bjsm.2007.043612v1
8. Noakes, T. D., R. J. Snow, and M. A. Febbraio. Linear relationship between the perception of effort and the duration of constant load exercise that remains. J Appl Physiol. 2004;96:1571-1573.
9. Ulmer, H. V. Concept of an extracellular regulation of muscular metabolic rate during heavy exercise in humans by psychophysiological feedback. Experientia. 1996;52:416-420.